Evaluating Relief Requirements for Reactive Processes with Unstable Intermediates

Evaluating reactive systems for relief is known to present many complexities compared with more common single-phase flow and non-reactive systems. In such cases it is important that the relief system designer understand, in addition to the physical and reactive characteristics of the materials, the nature and kinetic behavior of all reactions that could occur. Obtaining an accurate model of the reaction kinetics presents its own unique challenges. However, even when kinetics can be measured, the reaction mechanism may include unstable intermediates for which little or no physical property or vapor-liquid equilibrium data exists. Due to the instability of some of these species, measuring these parameters may be costly, difficult, or impossible. Consequently, while the reactive dynamics of the material can be predicted using these known kinetics, the physical behavior cannot. Even using the most sophisticated dynamic simulation tools available, there is still a critical knowledge gap preventing the proper evaluation of the system. This paper discusses in detail one method of developing physical property predictions for unknown components and using them, in conjunction with measured kinetic data, to evaluate a system for reactive relief cases.